@Panthro
there you put for how long nginx will reply with the cached response (for that response code, here 200). In this case each 1 second it will refresh the contents from upstream and start replying with the new content for another second and so on. It could be 1m, 1h, 1d, it all depends on how dynamic is your page. Even 1 second is enough to face a really burst rush of requests. That is the whole point of micro-caching.